Protective Adhesive Film, Method of Adhering Protective Adhesive Film to a Device, and Device Comprising Protective Adhesive Film

ABSTRACT

A protective adhesive film may include a polyurethane sheet and an adhesive layer disposed on at least a portion of a first major surface of the polyurethane sheet. The adhesive layer may comprise a pressure-sensitive adhesive that includes an acrylate polymer and a silicone macromer. The adhesive layer may adhere to a surface of an electronic device without the application of any liquid or additive to the adhesive layer or the surface of the electronic device.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/313,363, entitled “Method of Adhering a Protective Adhesive Film to aDevice and Device Comprising Protective Adhesive Film,” filed on Mar.12, 2010. This application further claims priority to U.S. ProvisionalApplication No. 61/316,185, entitled “Protective Adhesive Film, Methodof Adhering Protective Adhesive Film to a Device and Device ComprisingProtective Adhesive Film,” filed on Mar. 22, 2010. This applicationfurther claims priority to U.S. Provisional Application No. 61/359,690,entitled “Micro-Matte Protective Film, Method of Adhering Micro-MatteProtective Film to a Device and Device Comprising Micro-Matte ProtectiveFilm,” filed on Jun. 29, 2010. This application further claims priorityto U.S. Provisional Application No. 61/440,708, entitled “ProtectiveAdhesive Film, Method of Adhering Protective Adhesive Film to a Deviceand Device Comprising Protective Adhesive Film,” filed on Feb. 8, 2011.

BACKGROUND

The present invention relates generally to methods of applyingprotective films to electronic device surfaces and to devices comprisingprotective films.

Protective films are used to cover and protect a variety of materialsand devices from, for example, scratches or dents that may be impartedduring transport or use of the device. Protective films may be used toprotect, for example, the surface of digital electronic devicecomponents during manufacture, or may be adhered to a completed deviceto protect it from damage during normal day-to-day use. A variety ofprotective films are known, each having properties that may beadvantageous for some uses and disadvantageous for other uses. One formof protective film used in the art is coated on one side with a layer ofa dry pressure-sensitive adhesive that has sufficient tack to form asecure contact with the device while permitting slight repositioning ofthe film after adherence. Protective films are often transparent, andmay permit the use of touch-sensitive features of the electronic devicethrough the film.

Typically, when a dry protective film, particularly a protective filmhaving an adhesive layer, is applied to a surface, air is easily trappedbetween a device surface and the film during application, causing theappearance of bubbles. Bubbles are undesirable for aesthetic reasons butalso because their presence over an optical screen distorts images on ascreen viewed by a device user. Prior methods of eliminating trapped airbubbles beneath protective films utilize an aqueous solution or othersolvent to temporarily reduce adherence between a film and a device,permitting trapped air to be forced out by mechanical pressure. Knownmethods, for example, include spraying a protective film (or devicesurface) with water or another liquid, applying the wet film to thedevice surface to be protected (or applying the film to the wet devicesurface), and using pressure (e.g., with a squeegee) to smooth the filmand force out any trapped air bubbles. In doing so, the water or otherliquid is also forced out from between the film and the device surface,and collects at an edge of the film.

Thus, prior methods required introduction of a liquid to the outersurface of a device, requiring a user to take additional steps to removeliquid after a film is applied to a device. A significant disadvantageto using a wet solution to apply a protective film is potentialintroduction of liquid into an electronic device, for example, throughthe apertures for the speaker or head set jack. In some cases, liquidentering an interior housing of a device may cause a device to fail. Forthis reason, device manufacturers commonly include moisture sensitiveindicators within their devices to help diagnose device failure. In somecases, a manufacturer will void a device's warranty where inspection ofa device and its moisture indicators show exposure to moisture.

Another drawback of many protective films is the high visibility offingerprints, smudges or other marks on the film, resulting, forexample, from handling of a device. In particular, visibility offingerprints or other marks on films covering electronic device bodiesor display screens is aesthetically and functionally undesirable. Avisible residue over a display screen, for example, may distort thetransmission of light from the screen resulting in distortion of animage viewed on the screen. Matte surface treatments have been used toaddress this problem, but the application of typical matte surfaces overan optical screen reduces optical transmission.

SUMMARY

In one general aspect, a method of applying a protective film to adevice includes providing a protective film comprising an adhesive layercovered by a backing. The adhesive layer is disposed on a first majorsurface of the protective film. The method further includes removing atleast a portion of the backing to expose an adhesive area and contactingthe exposed adhesive area to a surface portion of a portable electronicdevice. The method further includes applying a pressure to a secondmajor surface of the protective film to press the exposed adhesive layeragainst the surface portion of the portable electronic device. Themethod may be performed without the application of any liquid to thedevice or the film.

In some embodiments, the adhesive layer comprises a pressure-sensitiveadhesive. The pressure-sensitive adhesive may include a copolymercomprising an acrylate polymer and a silicone macromer. In someembodiments, the method includes diffusing air bubbles through theprotective film.

The method may include applying the pressure with a smoothing device. Insome embodiments, the pressure may be applied to an exposed surface of acap sheet, the cap sheet disposed on the second major surface of theprotective film. In some embodiments, after applying the pressure to theexposed surface of the cap sheet, the method includes removing the capsheet to expose the second major surface of the protective film. In someembodiments, after the pressure is applied to the second major surfaceof the protective film, the method includes repositioning the protectivefilm.

The contacting step may include holding the protective adhesive film byat least one tab extending from the film. In some embodiments, afterholding the protective adhesive film by the at least one tab extendingfrom the film, the method includes removing the at least one tab fromthe polyurethane sheet.

In another general aspect, an electronic device comprises a displaysurface and a protective film disposed on the display surface. Anadhesive layer is disposed between and in contact with at least aportion of a first major surface of the protective film and the displaysurface. The protective film may adhere to the device withoutapplication of any liquid or solvent.

In some embodiments, the electronic device further includes a bezel thatis aligned along each edge of the display and a housing having aplurality of corners and sides, wherein the display surface may bedisposed on the housing. A second protective film may be disposed oneach corner of the housing, and/or a third protective film may bedisposed on the bezel. A second adhesive layer may be disposed betweenand in contact with at least a portion of a first major surface of thesecond protective film and each corner of the housing. A third adhesivelayer may be disposed between and in contact with at least a portion ofa first major surface of the third protective film and the bezel. Insome embodiments, the second and third protective films adhere to thedevice without application of any liquid or solvent.

In some embodiments, the protective film comprises polyurethane. In someembodiments, at least a portion of a second major surface of theprotective film may include a micro-matte surface structure. In someembodiments, no air bubbles are visible beneath the surface of theprotective adhesive film. In some embodiments, the protective film isair permeable. The adhesive may include an acrylate polymer and asilicone macromer.

In yet another aspect, a protective adhesive film includes apolyurethane sheet and an adhesive layer disposed on at least a portionof a first major surface of the polyurethane sheet. The adhesive layerincludes a pressure-sensitive adhesive that comprises a copolymercomprising an acrylate polymer and a silicone macromer. In someembodiments, the protective adhesive film is configured to adhere to adisplay of an electronic device without the application of any liquid tothe adhesive layer or the device.

The polyurethane sheet may be between about 75 microns and about 400microns in thickness. In some embodiments, the polyurethane sheetcomprises a polycaprolactone-based aliphatic thermoplastic urethane. Insome embodiments, at least a portion of a second major surface of thepolyurethane sheet comprises a micro-matte surface structure. In someembodiments, the protective adhesive film includes at least one tabextending from the polyurethane sheet. In some embodiments, a cap sheetis disposed on a second major surface of the polyurethane sheet.

In some embodiments, the adhesive layer is between about 12 microns andabout 75 microns in thickness. The adhesive may include a copolymer ofthe acrylate polymer and a silicone macromer side chain.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary adhesive film and a step for applying anadhesive film to an electronic device.

FIG. 2 illustrates an exemplary additional step for applying an adhesivefilm to an electronic device.

FIG. 3 illustrates an exemplary additional step for applying an adhesivefilm to an electronic device.

FIG. 4 illustrates an exemplary additional step for applying an adhesivefilm to an electronic device.

FIG. 5 illustrates an exemplary step for applying a protective adhesivefilm that includes a cap sheet layer to an electronic device.

FIG. 6 an exemplary additional step for applying a protective adhesivefilm that includes a cap sheet layer to an electronic device.

FIG. 7 illustrates an exemplary additional step for applying aprotective adhesive film that includes a cap sheet layer to anelectronic device.

FIG. 8 illustrates an exemplary additional step for applying aprotective adhesive film that includes a cap sheet layer to anelectronic device.

DETAILED DESCRIPTION

As used in the description below and in the appended claims, thesingular forms “a,” “an,” and “the” include plural references unless thecontext clearly dictates otherwise. Unless defined otherwise, alltechnical and scientific terms used in this document have the samemeanings as commonly understood by one of ordinary skill in the art. Asused in this document, the term “comprising” means “including, but notlimited to.” As used herein, the term “about,” when referring to avalue, means plus or minus 10% of the value.

This disclosure is not limited to the particular systems, devices andmethods described, as these may vary. Also, the terminology used in thisdocument is only for the purpose of describing particular versions orembodiments, and it is not intended to limit the scope.

Devices and methods are disclosed that avoid the need for an aqueoussolution or other liquid in applying a protective adhesive film to anelectronic device and removing trapped air bubbles. As described herein,a protective film comprising an adhesive layer (e.g., apressure-sensitive adhesive layer) may be adhered to a device surfacewithout the use of an aqueous solution to remove trapped air bubbles.Instead, trapped air bubbles are removed by applying pressure across thefilm surface to mechanically eliminate large (e.g., greater than 2-3 mmin diameter) air bubbles, while permitting smaller air bubbles to beeliminated over time. The adhesive film may be disposed on a first majorsurface of the protective adhesive film. As used in the document, theterm “major surface” refers to a planar surface of a sheet or layer of afilm. In general, a sheet will have two opposing major surfaces.

In some embodiments, a protective film may comprise a polyurethanesheet, e.g., a polycaprolactone-based aliphatic thermoplastic urethanesheet. A first major surface of a polyurethane sheet may be coated withone or more layers of a pressure-sensitive adhesive, such as a copolymercomprising an acrylate polymer and a silicone macromer. In someembodiments, the protective film is a polycaprolactone-based aliphaticthermoplastic urethane and comprises an adhesive layer consistingessentially of a copolymer of an acrylate polymer and silicone macromerside chains. A micro-matte surface structure may be formed on at least asecond major surface of the sheet, as described herein. In anotherembodiment, a protective film may comprise a polyurethane sheet, e.g., apolycaprolactone-based aliphatic thermoplastic urethane sheet. The sheetmay be coated on one side with a micro-matte layer, as described herein.

The protective adhesive film may comprise a polyurethane sheet, e.g., analiphatic polyester urethane-based sheet, e.g., a polycaprolactone basedaliphatic thermoplastic urethane sheet, coated on all or part of a firstmajor surface (or “backed”) with an adhesive layer. In some embodiments,the adhesive layer is a pressure-sensitive adhesive layer. Thepressure-sensitive adhesive layer (or coating) may be a copolymercomprising an acrylate polymer and a silicone macromer. In someembodiments, an adhesive layer thickness may be about 10 to about 100microns, about 12 to about 75 microns, about 25 to about 38 microns,about 30 microns, or about 35 microns. The pressure-sensitive adhesivelayer (or coating) may comprise an acrylate-silicone copolymer basedpressure-sensitive adhesive. The adhesive layer may comprise additionalcomponents, e.g., a tackifier or plasticizer, and may be a self-healingadhesive. The adhesive layer may be formed without the use of across-linker or photo-initiator. The adhesive layer may be preparedusing a thermal cure process. In some embodiments, the adhesive layer ismade of an adhesive that does not immediately firmly secure the film toa device and thus allows for slight repositionability of the film afterplacement on the device. For example, the adhesive layer may include anamount of silicone to permit repositionability. In some embodiments,unpolymerized silicone, tackifier, or other low molecular weightcomponents are included in the adhesive layer and migrate into thepolyurethane sheet and modify its characteristics. A polyurethane sheetcomprising an adhesive layer may be made more flexible or more impactresistant by the interaction with one or more such components from anadhesive.

In some embodiments, the adhesive layer comprises a polyacrylate-basedpressure-sensitive adhesive layer, having silicone macromer side chainmodifications of one or more acrylate ester groups. In some embodiments,the adhesive layer may be prepared from or comprise acrylic acid,methacrylic acid, esters of acrylic acid comprising 4 to 21 carbonatoms, esters of methacrylic acid comprising 5 to 21 carbon atoms,acrylamide, substituted acrylamides such as N,N-dimethyl acrylamide,styrene, substituted styrenes such as vinyl toluene, acrylonitrile,methacrylonitrile, N-vinyl pyrrolidone, N-vinyl caprolactam, vinylidenechloride, vinyl esters of carboxylic acids, 2-(2-ethoxyethoxy)ethylacrylate, 2-ethylhexyl acrylate, butyl acrylate, hydroxyethyl acrylate,hydroxypropyl acrylate, 2-carboxyethyl acrylate, ethoxyethyl acrylate,perfluorooctyl acrylate, isooctyl acrylate, divinylbenzene, vinylbenzylchloride, vinyl acetate, glycidyl methacylate, hydroethyl acetate,hydroxypropyl acetate, glacial acrylic acid, methyl acrylate, ethylacrylate, butyl acrylate, iso butyl acrylate or other acrylates, orcombinations thereof. In some embodiments, the pressure-sensitiveadhesive comprises acrylate and silicone in other polymer configurationsas known in the art. Suitable pressure-sensitive adhesives may bemanufactured by 3M Company of St. Paul, Minn. or other manufacturingcompanies.

The protective film may have a thickness from about 75 microns up toabout 400 microns. For example, the protective adhesive films used mayhave thicknesses including about 75 microns, about 100 microns, about150 microns, about 175 microns, about 200 microns, about 250 microns,about 300 microns, or about 350 microns. Different thicknesses may beused for different parts of a device. For example, an electronic devicemay use a 150 micron film for the device's optical screen and a 300micron film for the device's body. Such films may provide scratchresistance, impact resistance, or both, and may provide higher impactresistance to the parts of the device that are most likely to need it,while preserving the sensitivity and/or clarity of portions of thedevice that are less likely to require impact resistance.

The protective adhesive film to be adhered to a device optical screenmay have a shore hardness of between about 85A and 99A, or between about50D and 75D to provide a strong film with a flat surface with minimal orno surface distortion (e.g., “orange peel”). In some embodiments, theshore hardness of the protective adhesive film is about 60D or about93A. The protective adhesive film may allow for proper opticaltransmission and may provide a substantially smooth surface so that itbest mirrors the glass surface on the device. In addition to providingan aesthetic benefit, this allows for minimal or no reduction insensitivity and/or connectivity for touch screens.

The device body films may have a variety of surface types, includinganti-glare, glossy, or matte, and may be optically transparent,transparent with a matte texture, translucent or opaque. The film maycomprise UV absorbers. The films may be colored or uncolored. In someembodiments, the protective adhesive film may comprise a surface havinga micro-matte structure. Surface treatments may vary over a singledevice, i.e., a film covering an optical screen may have an anti-glaresurface while film covering a device body may have a matte surface. Aportion of a protective film to be adhered to the body of a device(portions not including the optical screen), the optical screen, or bothmay have a matte and/or a micro-matte finish or layer which mayeliminate or reduce fingerprints and adds additional “grip” to thedevice. Suitable protective films may be manufactured by Argotec Inc. ofGreenfield, Mass., or other similar manufacturing companies. In someembodiments, the adhesive coating or layer may be protected by aremovable backing (e.g., prior to adhering the protective film to adevice) before the protective adhesive film is adhered to a devicesurface.

A micro-matte surface structure is one that has a matte finish with anaverage roughness, Ra, between about 0.08 μm and about 0.22 μm, or about0.17 μm, or about 0.135 μm. In some embodiments, a micro-matte surfacestructure has an average maximum height, Rz, between about 0.50 μm andabout 1.20 μm, or about 1.11 μm, or about 1.23 μm. A micro-matte surfacestructure may have an average depth, Rmax, between about 1.30 μm andabout 1.50 μm, or about 1.40 μm.

In some embodiments, a micro-matte protective film is prepared byextrusion of a urethane resin onto a micro-matte textured casting sheetwhich, in some embodiments, may be a PET multi-layer film. The urethaneresin forms a film that, when removed from the casting sheet, retains amicro-matte surface texture on one side (e.g., a second major surface ofthe protective film) that mirrors the texture of the casting sheet.Thus, a film may be prepared by a single casting of urethane, ratherthan by addition of a micro-matte layer to a smooth urethane film.Alternatively, a micro-matte protective film may be prepared as aco-extrusion of at least two layers. Accordingly, a micro-matteprotective film may be prepared using multiple resins of varyinghardness such that its micro-matte structure may be harder and/or moredurable as may be required for specific applications. Alternatively, amicro-matte layer may be formed on a polyurethane sheet, for example, byextruding a resin onto a urethane film and contacting the resin with amicro-matte casting sheet to form a micro-matte surface texture. Themicro-matte protective film may comprise a pressure-sensitive adhesivelayer or layers, which may be the same or similar to thepressure-sensitive adhesive layer or layers described above. In someembodiments, the micro-matte textured casting sheet is the same ordifferent than the cap sheet described herein. The micro-matte structuremay cover all or part of a second major surface of a protective film.

In some embodiments, a polyurethane sheet coated with apressure-sensitive adhesive (e.g., to create a protective adhesive film)may be cut into predetermined shapes designed to fit particular portionsof digital electronic devices including, but not limited to, mobiletelephones, personal digital assistants, eReaders, computer notebooks,netbooks, tablets, cameras, game consoles, iPods and other MP3 players,navigation devices, and GPS devices. Such devices typically have adisplay screen and a housing. The cut film pieces of the protectiveadhesive film may be applied to the screen and/or other portions of thedigital device (such as an edge, side, corner or other portion of thehousing, and/or the bezel) to protect it from damage, using methodsdescribed in this document. In some embodiments, the film may be appliedto corners, edges and/or sides of the device to provide ashock-absorbing, impact-resistant skin for the device. The cut filmpieces may be designed such that they contain openings to correspond tovarious device components and thus do not block input or output ports,connections, jacks, or entry points for access to internal components ofthe device. The cut film may be flexible, to permit its application ontocurved surfaces smoothly without the appearance of gaps, wrinkles, orair bubbles.

In some embodiments, the protective adhesive film includes a cap sheet(e.g., a casting film and/or a casting sheet). The cap sheet may bedisposed on a second major surface of the protective film. The cap sheetmay be formed out of a material(s) that is sufficiently rigid that thepressure applied by a mechanical smoothing device (e.g., a squeegee)does not cause the cap sheet or the protective film to deform (e.g.,“orange peel”). Further, the cap sheet may withstand an increasedpressure from the mechanical smoothing device, which may result inreduced air bubbles between the protective film and an electronicdevice. Additionally, the cap sheet may protect the second major surfaceof the protective film during manufacture, transport, and/or theend-user installation processes. This may provide an advantage oversecondary application/release tapes that include a cured liquid for topcoating (e.g., a polyurethane and/or an acrylic material). The secondaryapplication/release tapes include an adhesive that may roughen ordistort the second major surface of the pressure adhesive layer, whichmay reduce the optical clarity of the protective film.

The cap sheet may be formed out of polyester. A polyester cap sheet(e.g., a laminating roll) that is about 2 mils thick may have sufficientrigidity and flexibility to prevent the cap sheet and/or the protectivefilm from deforming. Additionally, polyester may withstand the extrusiontemperature of the protective film (e.g., about 320-350° F.). The capsheet may comprise polyester, polypropylene, nylon, polyimide, andsimilar high-temperature resistant (e.g., able to resist the temperatureof the protective film extrusion, such as about 320-350° F.) and/or highmelt point films e.g., a melt point greater than the temperature of theprotective film extrusion, such as about 320-350° F.). The cap sheet maybe from about 0.92 mils (i.e., about 24 microns) to about 10 mils thick(i.e., about 254 microns). In some embodiments, the cap sheet may beabout 2 mils (i.e., about 24 microns) thick. The cap sheet may beembossed, brushed, or flat. In some embodiments, a micro-mane surfacestructure is defined in a cap sheet.

Suitable materials for the cap sheet and protective film may include oneor more of the following materials (or similar materials) manufacturedby Argotec, Inc. of Greenfield, Mass. (or other polyurethanemanufacturing companies): ARGOTHANE® aromatic polyethers/thermoplasticpolyurethane (part numbers 17103, 17200, 18103, 18212, 18214, 18215,18233, 18235, 18242, 18247, 18248, 18305, 18411, 18422, 18433, 18450-FR,18452-FR), ARGOTHANE® aromatic polyesters/thermoplastic polyurethane(part numbers 19102, 19103, 19205, 19422, 19424, 19426, D7101, 27303,27370, 28304, 29100, 29102, 29213, 29222, 29285, and/or 29300),ARGOTHANE® aliphatic polyesters (part numbers 3751 and/or AGKR),ARGOTHANE® aliphatic polycaprolactones/thermoplastic polyurethane (partnumber 46510) ARGOTHANE® waterproof breathable films/thermoplasticpolyurethane (part numbers TX1540 and/or TX2060), ARGOFLEX®waterproof-breathable films/thermoplastic polyurethane (part numbers TX1300, TX 1500, and/or TX2000), and/or ARGOTEC® film no. 49522.

In some embodiments, at least a portion of a surface of the cap sheet(e.g., a casting film and/or a casting sheet) has a texture (e.g.,brushed, ribs, ridges, grooves, raised dots, etc). The textured surfaceof the cap sheet may be disposed on the second major surface of theprotective film. The textured surface may cause micro air pockets toform between the textured surface and the second major surface of theprotective film. The micro air pockets are small air pockets that formin gaps between the textured surface and the second major surface of theprotective film. The micro air pockets may allow the cap sheet to bemore easily removed from the pressure-sensitive adhesive layer (e.g., byreducing a seal caused by two substantially smooth surfaces). In thealternative, the second major surface of the protective film may includea textured surface. However, this may decrease the optical clarity ofthe protective film and, therefore, may be less desirable to the enduser. In some embodiments, the cap sheet has a texture that defines amicro-matte surface on the second major surface of the protective film.

A mechanical smoothing device may be used to apply a pressure to anexposed surface of the cap sheet. The cap sheet may allow for the use ofa wider and/or more rigid mechanical smoothing device during theinstallation process as a result of the rigidity of the cap sheet. Forexample, the mechanical smoothing device may have approximately the samewidth as the entire electronic device (e.g., eReader, computer notebook,tablet, etc.) or a portion of the electronic device (such as a displayscreen) to which the protective adhesive layer is to be applied.Additionally, the cap sheet may be sufficiently rigid to withstand thepressure applied by the mechanical smoothing device to minimizeresulting damage (e.g., distortion) to the protective adhesive film. Thesmoothing device may be formed from a variety of materials, including athick, heavy gauge paper (e.g., greater than about 50 mils thick,between about 50-150 mils thick, between about 50-90 mils thick, betweenabout 50-80 mils thick, between about 60-80 mils thick, or about 70 milsthick), polyvinyl chloride acetate (PVCA), unplasticized polyvinylchloride (uPVC), silicone rubber, ethylene propylene diene monomer(M-class) rubber (EPDM rubber), and/or other semi-rigid rubbers, and/orrigid plastics, such as rigid polyethylene (e.g., HDPE, MDPE, or LDPE),polyvinyl chloride (PVC), and/or polypropylene. For example, thesmoothing device may be formed from silicone rubber and/or EPDM rubberthat is about 60 to 90 Shore A durometer in hardness.

A wider mechanical smoothing device may provide several advantages. Forexample, a wider mechanical smoothing device only needs to be appliedonce (as it may be about the same width as a screen of an eReader,etc.), thereby decreasing installation time. Additionally, a widermechanical smoothing device may minimize unintended skewing,repositioning and/or stretching of the protective adhesive film that mayoccur as a result of multiple squeegee applications (e.g., in differentdirections with respect to the screen of an eReader, etc.). A wider andharder mechanical smoothing device allows the user to apply an increaseddownward force/pressure on the cap sheet, resulting in an increasedadherence of the protective adhesive film to the electronic deviceand/or reduced air bubbles between the protective adhesive film and theelectronic device.

In some embodiments, the protective film includes a body and at leastone tab that extends outwardly from the body. In some embodiments, theprotective film includes two tabs, for example, on opposing sides of theprotective film. The tabs may be positioned in the middle of eachopposing side, or in any other position along the edge of the protectivefilm. The tabs may function as grab handles to allow a user to moreaccurately position the protective adhesive film and cap sheet on theelectronic device and/or to reduce fingerprints on the protectiveadhesive film. In some embodiments, the tabs include perforations,allowing the user to more easily remove the tabs after installation.

FIG. 1 illustrates an exemplary first step for applying an adhesive film(e.g., a protective adhesive film and/or a micro-matte protective film)to an electronic device. In this step, a portion of a backing layer 20is removed from an adhesive film 10 to expose an adhesive area 30. Theadhesive area 30 is disposed on at least a portion of a first majorsurface 40 of the protective adhesive film 10. Prior to removing thebacking layer 20, the adhesive film 10 may be modified by cutting (e.g.,by die cutting, plotter cutting, or other methods) to create segmentsmatched in size and shape to chosen surface areas on a particular deviceto be protected. Alternatively, the adhesive film 10 may be pre-cut tomatch a desired area on an electronic device.

Referring to FIG. 2, after the backing layer 20 is partially or fullyremoved, the adhesive area 30 may be positioned to contact and alignwith an exposed surface portion 50 of an electronic device 60 (e.g., adisplay surface). In some embodiments, the exposed surface portion 50may be a small, large, or an entire portion of an exposed surface 70 ofthe electronic device 60. In some embodiments, the adhesive film 10and/or the adhesive area 30 are aligned to the electronic device 60(e.g., aligned to the surface portion 50, e.g., an edge of the exposedsurface 70). For example, openings 75 in the adhesive film 10 may bealigned to corresponding components 65 (e.g., input and/or output ports,buttons, etc.) of the electronic device 60. In some embodiments, priorto contacting the adhesive film 10 to the electronic device 60, at leasta portion of the exposed surface 70 of the electronic device may becleaned, for example, by rubbing or polishing the at least a portion ofexposed surface 70 with a dry tissue or towelette.

The film 10 (e.g., a protective adhesive film and/or a micro-matteprotective film) may be applied to the electronic device 60 “as is.”There is no need to apply any liquid or other additive to any portion ofthe exposed surface 70 or the adhesive area 30 at any time during theprocess.

As illustrated in FIG. 3, after the film 10 is aligned to the device 60,the backing layer 20 is completely removed from the first major surface40 of the film 10, and the remaining adhesive area 30 of the film 10 isaligned to contact the device 60.

Referring to FIG. 4, a mechanical smoothing device 100 (e.g., asqueegee, a device having a resilient edge, or a hand) may be used toapply a pressure to the second major surface 90 of the film 10. Thepressure may cause the adhesive area 30 to press against the exposedsurface portion 50 of the electronic device 20. In some embodiments, themechanical smoothing device 100 applies the pressure from a central area105 to an edge 110 of the second major surface 90 continuing indifferent radial directions from the central area 105 across the secondmajor surface 90. In some embodiments, the mechanical smoothing device100 applies the pressure starting at or near a trapped air pocket or anair bubble and continues to an edge 110. Any haze or remaining trappedair bubbles, if less than about 2-3 mm in diameter, may be left todiffuse out through the protective adhesive film 10 (e.g., anair-permeable film), generally disappearing within 24 hours.

In some embodiments, the method may include repositioning the film 10(e.g., a protective adhesive film and/or a micro-matte protective film)after it has been adhered to the exposed surface portion 50 of thedevice 20. For example, the method may include lifting a portion of thefilm 10 away from the exposed surface portion 50 of the device 20 andreapplying (e.g., re-contacting) the portion to the exposed surfaceportion 50 of the device 20, which may be helpful in repositioningand/or re-aligning the film 10 and/or in removing air bubbles. In someembodiments, additional mechanical smoothing (e.g., by hand or with amechanical device) may be used to ensure that the film 10 is adhered tothe edges 110 of the device 20.

FIGS. 5-8 illustrate an alternative procedure that may be used forlarger electronic devices, such as tablets, notebooks, and notebooks. Inthis embodiment, the protective adhesive film includes a cap sheet layer(e.g., a casting film and/or a casting sheet). Referring to FIG. 5, aportion of a backing layer 420 is removed from an adhesive film 410 toexpose an adhesive area 430. In some embodiments, the adhesive film 410is a micro-matte protective adhesive film. The adhesive area 430 isdisposed on at least a portion of a first major surface 440 of theprotective adhesive film 410. A cap sheet 510 is disposed on a secondmajor surface of the protective adhesive film 410. Prior to removing thebacking layer 420, the film 410, together with the cap sheet 510 as onepiece or separately from the cap sheet 510, may be shaped by cutting(e.g., by die cutting, plotter cutting, or other methods) to createsegments, with a cap sheet 510 layered on the adhesive film 410, matchedin size and shape to chosen surface areas on a particular device to beprotected. Alternatively, the protective adhesive film 410 and cap sheet510 may be pre-cut to match a desired area on an electronic device.

After the adhesive is exposed, FIG. 6 illustrates that the adhesive area430 may be contacted to an exposed surface portion 450 of an electronicdevice 460 (e.g., a display surface). In some embodiments, the exposedsurface portion 450 may be any portion of exposed surface 470 includingthe entire exposed surface 470. In some embodiments, the adhesive film410 and/or the adhesive area 430 may be positioned to contact and alignwith an exposed surface portion 450 of the electronic device 460. Forexample, openings 475 in the adhesive film 410 may be aligned tocorresponding components 465 (e.g., input and/or output ports, buttons,etc.) of the electronic device 460. In some embodiments, at least oneoptional tab 415 extends from the adhesive film 410. A user may hold theat least one optional tab 415 while positioning, contacting, and/oraligning the adhesive area 430 to the exposed surface portion 450 of theelectronic device 460. In some embodiments, prior to contacting theadhesive film 410 to the electronic device 460, at least a portion ofexposed surface 470 of the electronic device may be cleaned, forexample, by rubbing or polishing the at least a portion of exposedsurface 470 with a dry tissue or towelette. In some embodiments, noliquid or other additive is applied to the adhesive film 410, theadhesive area 430, and/or the electronic device 460.

Referring to FIG. 7, a mechanical smoothing device 500 (e.g., asqueegee, oversized squeegee, a device having a resilient edge, or ahand) may be used to apply a pressure to the cap sheet 510 disposed on asecond major surface 490 of the film 410. The pressure may causes theadhesive area 430 to press against the exposed surface portion 450 ofthe electronic device 460 (as depicted in FIG. 6). The mechanicalsmoothing device 500 may be applied starting at an edge 515 of theelectronic device 420 and proceeding across the width 520 of theelectronic device 420. An optional second mechanical smoothing step maybe applied in the opposite direction of the first mechanical smoothingstep. After pressure is applied with the mechanical smoothing device500, the cap sheet 510 is removed (e.g., peeled off) to expose thesecond major surface 490 of the film 410, as illustrated in FIG. 8. Anyhaze or remaining trapped air bubbles, if less than about 2-3 mm indiameter, may be left to diffuse out through the protective adhesivefilm 410 (e.g., an air-permeable film), generally disappearing within 24hours. For example, air bubbles may diffuse into the first major surface440 of the film 410 and out the second major surface 490 of the film410. In some embodiments, after the mechanical smoothing step, theoptional hold tabs 415 may be removed from the film 410 by pulling alongoptional perforations (not shown) or by cutting off the hold tabs 415.

The method improves the adherence of the film to the surface of thedevice, and provides a higher quality (e.g., less damaged, moretransparent, and/or more accurately placed) protective film. The methodfurther reduces the number of remaining trapped air bubbles. The methodfurther reduces the installation time of applying a protective film toan electronic device.

1. A method of applying a protective film to a device, comprising:providing a protective film comprising an adhesive layer covered by abacking, wherein the adhesive layer is disposed on a first major surfaceof the protective film; removing at least a portion of the backingexpose an adhesive area; contacting the exposed adhesive area to asurface portion of a portable electronic device; and applying a pressureto a second major surface of the protective film to press the exposedadhesive layer against the surface portion of the portable electronicdevice, wherein the method is performed without the application of anyliquid to the device or the film.
 2. The method of claim 1 wherein theadhesive layer comprises a pressure-sensitive adhesive, thepressure-sensitive adhesive compres a copolymer comprising an acrylatepolymer and a silicone macromer.
 3. The method of claim 1 furthercomprising repositioning the protective film after the applying step. 4.The method of claim 1 further comprising applying the pressure with asmoothing device.
 5. The method of claim 1 further comprising applyingthe pressure to an exposed surface of a cap sheet, the cap sheetdisposed on the second major surface of the protective film.
 6. Themethod of claim 5 further comprising, after applying the pressure to theexposed surface of the cap sheet, removing the cap sheet to expose thesecond major surface of the protective film.
 7. The method of claim 1wherein the contacting step comprises holding the protective adhesivefilm by at least one tab extending from the film.
 8. The method of claim7 further comprising, after holding the protective adhesive film by atleast one tab extending from the film, removing the at least one tabfrom the polyurethane sheet.
 9. The method of claim 1 further comprisingdiffusing air bubbles through the protective film.
 10. An electronicdevice comprising: a display surface; a protective film disposed on thedisplay surface; and an adhesive layer between and in contact with atleast a portion of a first major surface of the protective film and thedisplay surface, wherein the protective film adheres to the devicewithout application of any liquid or additive.
 11. The electronic deviceof claim 13, further comprising: a bezel that is aligned along each edgeof the display; a housing having a plurality of corners and sides, thedisplay surface disposed on the housing; a second protective filmdisposed on each corner of the housing; a third protective film disposedon the bezel, a second adhesive layer between and in contact with atleast a portion of a first major surface of the second protective filmand each corner of the housing; a third adhesive layer between and incontact with at least a portion of a first major surface of the thirdprotective film and the bezel; wherein the second and third protectivefilms adhere to the device without application of any liquid oradditive.
 12. The electronic device of claim 10 wherein at least aportion of a second major surface of the protective film comprises amicro-matte surface structure.
 13. The electronic device of claim 10wherein the protective film comprises polyurethane.
 14. The electronicdevice of claim 10 wherein the adhesive comprises an acrylate polymerand a silicone macromer.
 15. The device of claim 10 wherein no airbubbles are visible beneath the surface of the protective adhesive film.16. The device of claim 10 wherein the protective film is air permeable.17. A protective adhesive film comprising a polyurethane sheet and anadhesive layer disposed on at least a portion of a first major surfaceof the polyurethane sheet, wherein the adhesive layer comprises apressure-sensitive adhesive, the pressure-sensitive adhesive comprisinga copolymer comprising an acrylate polymer and a silicone macromer. 18.The protective adhesive film of claim 17 wherein the polyurethane sheetis between about 75 microns and about 400 microns in thickness.
 19. Theprotective adhesive film of claim 17 wherein the adhesive layer isbetween about 12 microns and about 75 microns in thickness.
 20. Theprotective adhesive film of claim 17 wherein the polyurethane sheetcomprises a polycaprolactone based aliphatic thermoplastic urethane. 21.The protective film of claim 17 wherein the adhesive comprises acopolymer of the acrylate polymer and a silicone macromer side chain.22. The protective adhesive film of claim 17 wherein at least a portionof a second major surface of the polyurethane sheet comprises amicro-matte surface structure.
 23. The protective adhesive film of claim17 further comprising at least one tab extending from the polyurethanesheet.
 24. The protective adhesive film of claim 17 further comprising acap sheet disposed on a second major surface of the polyurethane sheet.25. The protective adhesive film of claim 17 wherein the protectiveadhesive film is configured to adhere to a display of an electronicdevice without the application of any liquid to the adhesive layer orthe device.